County of Hawaii - Flood Awareness

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Build with Flooding in Mind

You can reduce flood damage by flood proofing, elevating a home or even moving a home out of harm’s way. Know your flood zone and avoid building in a floodplain—any land area that can be inundated by water from any source.

If you must build, fill or otherwise develop in a floodplain, follow County of Hawai‘i floodplain management permit requirements stated in the Hawai‘i County Code Chapter 27. To minimize private losses due to flooding, the code outlines methods and provisions for development, initial construction, diverting floodwaters or altering natural floodplains, stream channels and natural barriers. Additional standards may apply for coastal high hazard areas (see Section 27-23 of Chapter 27).

County Requirements

Obtain the necessary building permits from the Department of Public Works Building Division and follow the Hawai‘i County General Plan and the County Code (see Chapter 5) when building or maintaining property. All development (not just the construction of buildings) in floodplain areas requires County permits.

Elevation Certificates and Supplemental Forms

Hawai‘i County participates in the National Flood Insurance Program (NFIP), which requires elevation certificates for all new and substantially improved buildings. 

Along with elevation certificates, the County requires supplemental forms for structures or improvements in Special Flood Hazard Area (SFHA) or within the County's “Buffer Zone.”

  • For additional information on elevation certificates, visit the FEMA website or call the Hawai‘i County Floodplain Manager, 808-961-8327.

Detached Accessory Structures Within Designated Flood Zones

Completion of the Detached Accessory Structure in A Zone requires the applicant to engage a professional before submitting plans. This may cause needless expense and effort if the property is exempt. Please contact the Engineering Division at 961-8327 or email for additional information.

Resources for Flood Mitigation

FEMA and other organizations offer publications and online information to help you reduce potential flood damage. Detailed information about flood resistant construction techniques is available in the following publications.

Both publications are available at libraries in Hawai‘i County or can be downloaded.  FEMA publications are free.

   Additional Online Resources

  • Wet and Dry flood-proofing information from the Federal Alliance for Safe Homes Web site.
  • Protecting Building Utilities From Flood Damage (FEMA 348). This publication is intended to assist developers, architects, engineers, builders, code officials and homeowners to construct with building utility systems that are designed and built so that the buildings can be re-occupied and fully operational as soon as electricity and sewer and water are restored to the neighborhood.
  • FEMA’s Protect Your Property from Flooding is a series of eight publications with topics ranging from inspecting and maintaining the building to installing protective devices.
  • University of Hawai‘i at Hilo has reminders to elevate main breakers, waterproof exterior walls, anchor water tanks and clear debris from storm drains and gutters.

Report illegal floodplain development to Department of Public Works at 808-961-8327.